package com.ctrw.utils;

import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;

import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;

//全局唯一id生成器
@Component
public class RedisIdWorker {
    /*
    开始时间戳
     */
    private static final long BEGIN_TIMESTAMP = 1640995200L;
    /*
    序列号的位数
     */
    private static final int COUNT_BITS = 32;

    @Resource
    StringRedisTemplate stringRedisTemplate;

    public long nextId(String keyPrefix) {
        //1、生成时间戳
        LocalDateTime now = LocalDateTime.now();
        long nowSecond = now.toEpochSecond(ZoneOffset.UTC);
        long timeStamp = nowSecond - BEGIN_TIMESTAMP;
        //2、生成序列号
        //2.1、获取当前日期精确到天
        String date = now.format(DateTimeFormatter.ofPattern("yyyy:MM:dd"));
        //2.2、自增长
        long count = stringRedisTemplate.opsForValue().increment("icr:" + keyPrefix + ":" + date);
        //3、拼接并返回
        return timeStamp << COUNT_BITS | count;
    }

}
